This is a multidisciplinary research program directed at an understanding of the fundamental mechanisms of cardiovascular disease, and of the basis for its optimal treatment in patients. In addition to normal and abnormal cardiovascular function in human subjects, experimental observations in animals and in biophysical and biomathematical models are included. Broad goals of the program include an improved concept of organ and system function relative to cardiac surgery, the pathogenesis and pathophysiology and treatment of ischemic heart disease, and mechanisms of sudden death. Ventricular function is studied in man, in intact dogs, and in isolated papillary muscles. Function of the sinus node and AV conduction system are investigated in man, and with special preparations in the dog, and are correlated with light and electron microscopic studies of these regions. Functional research on blood vessels is conducted in man, in experimental animals and in biophysical models. Automation of clinical diagnosis is being studied with numerous non-invasive methods, multiple dipole electrocardiography and special types of stress testing. New programs include cardiac electrophysiology during human surgery, immunology and tissue biochemistry and molecular biophysics of the heart and vessels. These and other research projects interrelate in the common goal of elucidating normal and abnormal cardiovascular function.